2 research outputs found
Computational Study on Ring Saturation of 2‑Hydroxybenzaldehyde Using Density Functional Theory
Bio-oil
produced from pyrolysis of lignocellulosic biomass consists
of several hundreds of oxygenated compounds resulting in a very low
quality with poor characteristics of low stability, low pH, low stability,
low heating value, high viscosity, and so on. Therefore, to use bio-oil
as fuel for vehicles, it needs to be upgraded using a promising channel.
On the other hand, raw bio-oil can also be a good source of many specialty
chemicals, e.g., 5-HMF, levulinic acid, cyclohexanone, phenol, etc.
In this study, 2-hydroxybenzaldehyde, a bio-oil component that represents
the phenolic fraction of bio-oil, is considered as a model compound
and its ring saturation is carried out to produce cyclohexane and
cyclohexanone along with various other intermediate products using
density functional theory. The geometry optimization, vibrational
frequency, and intrinsic reaction coordinate calculations are carried
out at the B3LYP/6-311+gÂ(d,p) level of theory. Furthermore, a single
point energy calculation is performed at each structure at the M06-2X/6-311+gÂ(3df,2p)//B3LYP/6-311+gÂ(d,p)
level of theory to accurately predict the energy requirements. According
to bond dissociation energy calculations, the dehydrogenation of formyl
group of 2-hydroxybenzaldehyde is the least energy demanding bond
cleavage. The production of cyclohexane has a lower energy of activation
than the production of cyclohexanone
Quantum chemical study on gas phase decomposition of ferulic acid
<p>Ferulic acid, representing phenolic fraction of bio-oil, is considered to be a model compound in this study for its decomposition into various end products such as ethylbenzene, eugenol, <i>cis</i>-isoeugenol, vanillin, 4-ethylguaiacol, guaiacol, and acetovanillone using density functional theory approach. Results of bond dissociation energies indicate that cleavage of methyl group from ferulic acid is the lowest energy-demanding bond scission amongst all 14 bond cleavages. Primary end product by decomposition of ferulic acid is found to be ethylbenzene and its production occurs through the formation of intermediate products such as 4-hydroxycinnamic acid, cinnamic acid and styrene. Demethoxylation of ferulic acid gives rise to the production of 4-hydroxycinnamic acid which further undergoes the formation of cinnamic acid by dehydroxylation reaction route. The formation of cinnamic acid in this study is carried out using three reaction schemes 1–3 and its further reduction to ethylbenzene is performed using two reaction possibilities. Finally, favourable pathway is found to be decarboxylation of cinnamic acid to produce vinylbenzene followed by the production of ethylbenzene using hydrogenation of C=C chain double bond. Furthermore, thermochemistry of each reaction scheme is performed at atmospheric pressure and at a wide range of temperature of 598–898 K.</p